Alcohol use during adolescence and early adulthood can adversely impact occupational, health, and social development. College students have a particularly high prevalence of heavy alcohol use. However, college students have highly variable alcohol use patterns that are influenced by numerous personal and contextual factors. Demand curve analysis accommodates such factors in its description of individual resource allocation to alcohol-related behavior. Preliminary evidence suggests that demand curve measures are an innovative method to evaluate an individual's alcohol problem use and their responsiveness to treatment. This proposal seeks to seize a unique opportunity to incorporate this innovative measure of alcohol demand into the College Health Intervention Projects Study (CHIPS), the largest ongoing clinical trial of brief intervention in college students (R01 AA014685-01). The results will be used to inform the following aims: 1) to estimate and characterize alcohol demand curves, 2) to estimate econometrically the ability of alcohol demand curves to distinguish between levels of alcohol use, 3) to estimate econometrically the ability of alcohol demand curves to predict responsiveness to brief intervention, 4) to evaluate whether changes in alcohol demand curves correlate with brief intervention outcomes, 5) to construct models of alcohol use trajectory, and 6) to assess whether demand curves predict alcohol use trajectories. Results will determine how well demand curve characteristics - an innovative measure of alcohol use behavior - assess and predict alcohol-related risk and treatment responsiveness among a college population.